The devastating tragedy came just three weeks after the troops began their tour of duty.

It is believed their vehicle caught fire after the blast and ammunition on board exploded – causing a fierce blaze from which nobody escaped.

It was the single biggest British loss from enemy action in Afghanistan since the conflict began in 2001 and took the total number of deaths of UK service personnel to 404.

Experts say the huge IED that destroyed their Warrior troop carrier would have taken several men a number of hours to put in place.

The Warrior – one of the Army’s most important strike weapons – is currently being given a £1billion upgrade following concerns about the protection it offers to troops.

But the modified vehicles are not due to come into service until 2020.

Video Loading

Video Unavailable

Click to playTap to play

The video will start in 8Cancel

Play now

Video will play in

Share this video

Watch Next

As the deaths were announced, David Cameron said it was a “desperately sad day” for the country and for the families of those involved.

Ministry of Defence officials revealed five of the troops came from 3rd Battalion The Yorkshire Regiment. The other soldier killed in Tuesday night’s blast was from 1st Battalion The Duke of Lancaster’s Regiment.

All six had flown out from Brize Norton on Valentine’s Day for a six-month posting.

They died as they patrolled the border between Helmand and Kandahar provinces.

MoD officials believe their Warrior, the leading one of two on the patrol, hit either a Taliban-planted IED or an anti-tank mine from the war with the Soviet Union in the 1980s.

The blast came shortly after 7pm local time northwest of Durai Junction, where a road east from Gereshk meets another going north to Lashkar Gah.

Local resident Abdul Ali said the Warrior “burned all night” after the explosion.

Recovery teams were initially unable to reach the stricken Warrior or retrieve the bodies because of a severe sandstorm and the men were officially only listed as “missing”.

But the MoD informed the soldiers’ families of what had happened – and warned them to expect the worst.

As the grim news was confirmed, Mr Cameron said: “It is a reminder of the huge price that we are paying for the work we are doing in Afghanistan and the sacrifice that our troops have made and continue to make.”

He also revealed he would be discussing the situation in Afghanistan with President Barack Obama on his visit to the US next week.

Devastated: A woman lays a floral tribute at the 3rd Battalion The Yorkshire Regiment's barracks in Warminster Wiltshire (Photo: PA)

Remembrance: Mourners and well-wishers have headed to The Yorkshire Regiment's barracks in Warminster Wiltshire to pay tribute (Photo: PA)

Although no date has been set for a complete withdrawal from Afghanistan, the PM announced last year that the military’s “combat role” would be over by the end of 2014.

Afghan troops are expected to take “lead responsibility” for security in 2013, when up to 4,000 British troops could be brought home.

Around 500 will be withdrawn this year, leaving around 9,000 UK service personnel in the country.

Defence Secretary Philip Hammond insisted today that morale among British troops serving in Afghanistan remained "extremely high" because they know they have an important job to do.

He told ITV's Daybreak programme: "The people on the ground are acutely conscious of the risks that they are running but they are also incredibly proud of the job that they are doing - and rightly so - and hugely satisfied by the level of public support that they have back home.

"Morale on the ground in Afghanistan is extremely high, and it's high because the servicemen and women there know that they are doing a job and and are doing it well and that is their professional commitment to get that job done."

Fallen heroes: Tributes at Somme Barracks at Catterick Garrison, the home of the 1st Battallion Duke of Lancaster's Regiment who are believed to have lost a soldier (Photo: PA)

Mr Hammond defended the level of protection offered by the vehicle the six soldiers were travelling in when they died.

He said: "The Warrior is the most heavily armoured vehicle that we have. It has been very heavily upgraded following some criticism that was made of the level of protection by a coroner. That programme of upgrading has been completed.

"In fighting a war you can never be 100% protected. We don't know what happened in this incident - it looks like a massive IED that had a catastrophic impact on the vehicle.

"Obviously we will look at any lessons that can be learnt but talk to soldiers on the ground - they will tell you that there is a trade-off between level of armour and manoeuvrability.

"You can put more armour on a vehicle but then you make it slower and less manoeuvrable and that in itself creates risk."

General Sir David Richards, the head of the Armed Forces, insisted that Britain's military strategy in Afghanistan would not change despite the deaths, adding: "We will hold our nerve."

Prime Minister David Cameron said the news marked a "desperately sad day for our country", while Labour leader Ed Miliband saluted "all of our fallen and those who continue to serve in the face of the gravest danger".

Floral tributes continued to be left at Battlesbury Barracks in Warminster, Wiltshire, the home of 3rd Battalion The Yorkshire Regiment.

More than a dozen children from the local school, St George's Catholic Primary, walked with their teacher to the barracks entrance.

One girl placed a bunch of flowers next to the other tributes and then rejoined her classmates as they stood quietly and prayed.

The children's tribute read: "Our thoughts and prayers are with you all. God bless. From the staff and pupils of St George's Catholic Primary School, Warminster."

Video Loading

Video Unavailable

Click to playTap to play

The video will start in 8Cancel

Play now

Video will play in

Share this video

Watch Next

On the front line: A Merlin helicopter taking off from Camp Bastion in the Helmand province of Afghanistan (Photo: PA)

Constant danger: A British soldier on patrol in Afghanistan (Photo: PA)

Earlier, 13 civilian staff, who work at the barracks as cleaners, paid their respects to the dead soldiers.

They each left flowers and then held hands in a semi-circle as they stood in reflection for a minute's silence.

One woman fought back tears and was comforted by a colleague.

Floral tributes were being left by both service families and those with no connection to military life but who were touched by the tragic loss.

One bouquet said: "From one regimental family to another. Our thoughts are with you at this sad time. Rest in peace. The Warminster branch of the Royal Irish Rangers."

Another card said: "RIP to the soldiers. Our sympathy is with you. Miss you guys."

Another said: "We do not come from an Armed Forces family and are just local residents. However, we consider each and everyone of you as family and see you as 'our boys'.

"Deepest sympathy to your family and friends at this very sad time. RIP. Love always Bryers and Dancer family, Westbury xxxxxx."

Another tribute said simply: "Stand easy - your duty is done. The world is safer."